/*********************************************************************
 * Copyright (C) 2002 Andrew Khan
 * <p>
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 * <p>
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 * <p>
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 ***************************************************************************/

package jxl.read.biff;

import jxl.CellType;
import jxl.DateCell;
import jxl.DateFormulaCell;
import jxl.biff.FormattingRecords;
import jxl.biff.FormulaData;
import jxl.biff.WorkbookMethods;
import jxl.biff.formula.ExternalSheet;
import jxl.biff.formula.FormulaException;
import jxl.biff.formula.FormulaParser;

import java.text.NumberFormat;

/**
 * A date formula's last calculated value
 */
class DateFormulaRecord extends DateRecord
        implements DateCell, FormulaData, DateFormulaCell {
    /**
     * The formula as an excel string
     */
    private String formulaString;

    /**
     * A handle to the class needed to access external sheets
     */
    private ExternalSheet externalSheet;

    /**
     * A handle to the name table
     */
    private WorkbookMethods nameTable;

    /**
     * The raw data
     */
    private byte[] data;

    /**
     * Constructs this object from the raw data
     *
     * @param t the basic number formula record
     * @param fr the formatting records
     * @param es the external sheet
     * @param nt the name table
     * @param nf flag indicating whether the 1904 date system is in use
     * @param si the sheet
     */
    public DateFormulaRecord(NumberFormulaRecord t, FormattingRecords fr,
                             ExternalSheet es, WorkbookMethods nt,
                             boolean nf, SheetImpl si) throws FormulaException {
        super(t, t.getXFIndex(), fr, nf, si);

        externalSheet = es;
        nameTable = nt;
        data = t.getFormulaData();
    }

    /**
     * Returns the cell type
     *
     * @return The cell type
     */
    public CellType getType() {
        return CellType.DATE_FORMULA;
    }

    /**
     * Gets the raw bytes for the formula.  This will include the
     * parsed tokens array.  Used when copying spreadsheets
     *
     * @return the raw record data
     */
    public byte[] getFormulaData() throws FormulaException {
        if (!getSheet().getWorkbookBof().isBiff8()) {
            throw new FormulaException(FormulaException.BIFF8_SUPPORTED);
        }

        // Data is already the formula data, so don't do any more manipulation
        return data;
    }

    /**
     * Gets the formula as an excel string
     *
     * @return the formula as an excel string
     * @exception FormulaException
     */
    public String getFormula() throws FormulaException {
        // Note that the standard information was lopped off by the NumberFormula
        // record when creating this formula
        if (formulaString == null) {
            byte[] tokens = new byte[data.length - 16];
            System.arraycopy(data, 16, tokens, 0, tokens.length);
            FormulaParser fp = new FormulaParser
                    (tokens, this, externalSheet, nameTable,
                            getSheet().getWorkbook().getSettings());
            fp.parse();
            formulaString = fp.getFormula();
        }

        return formulaString;
    }

    /**
     * Interface method which returns the value
     *
     * @return the last calculated value of the formula
     */
    public double getValue() {
        return 0;
    }

    /**
     * Dummy implementation in order to adhere to the NumberCell interface
     *
     * @return NULL
     */
    public NumberFormat getNumberFormat() {
        return null;
    }
}
